1. Field of the Invention
The present invention relates to an interpolation technology adapted to a picture motion, in particular to a deinterlacing apparatus and a method thereof which are capable of improving definition of a picture by performing edge direction detection and pixel interpolation.
2. Description of the Background Art
In the conventional image processing method, a deinterlacing method is a method converting an interlaced scanning type image signal into a progressive scanning type image signal. It will now be described with reference to accompanying FIGS. 1 and 2Axcx9c2C.
FIG. 1 illustrates a picture in accordance with the general interlacing method.
As depicted in FIG. 1, in the interlaced scanning type image data, a picture of one frame is implemented with an odd field and an even field, namely, two fields.
However, according to a type of a display apparatus, a picture is implemented by processing the interlaced scanning type image signal as a progressive scanning type image signal used in a computer monitor etc. without processing it as the interlaced scanning type image signal.
Herein, in order to process the interlaced scanning type image signal on a display apparatus for processing the progressive scanning type image signal, an additional system for converting the interlaced scanning type image signal into the progressive scanning type image signal has to be installed inside of the display apparatus.
As depicted in FIGS. 2Axcx9c2C, a converting method for converting the interlaced scanning type image signal into the progressive scanning type image signal can be implemented in many ways.
FIG. 2A illustrates a line repetition in accordance with the conventional technology.
As depicted in FIG. 2A, the line repetition implements one frame by repeating line information of the present field.
FIG. 2B illustrates an intra-field interpolation without motion-compensation in accordance with the conventional technology.
As depicted in FIG. 2B, the intra-field interpolation without motion-compensation implements one frame by inserting a former field line between the present field line.
FIG. 2C illustrates an intra-field interpolation in accordance with the conventional technology.
As depicted in FIG. 2C, the intra-field interpolation implements a new field by inserting xc2xd divided data of two lines into region between the two lines on one field.
The line repetition can be implemented as a simple hardware, however the image quality lowers after the interpolation using the line repetition method.
In addition, the intra-field interpolation without motion-compensation also can be implemented as a simple hardware, however a picture is deteriorated due to an error occurred in the interpolation of a motion picture.
And, the intra-field interpolation is better than the line repetition in the image quality and error occurrence aspect, however the picture is deteriorated when a still picture is interpolated.
In other words, as depicted in FIGS. 2Axcx9c2C, the interpolation methods all have the image quality lowering problem after the interpolation.
Accordingly, a motion-compensation interpolation for interpolating the present picture by using field data of the former picture and field data of a picture to be implemented is suggested.
The motion-compensation interpolation divides a picture into a plurality of blocks and finds a motion vector about each block by using timely consecutive field data on the basis of the present field data, and interpolates the present frame picture by referring to the motion vector.
An image quality can be improved by the motion-compensation interpolation, however, it is implemented as a complicated hardware.
Accordingly, in order to solve the problem of the motion-compensation interpolation, a motion adaptive interpolation for interpolating a frame in accordance with a motion by assuming the degree of the motion is suggested.
The motion adaptive interpolation can be implemented as a simple hardware on the comparison with the motion-compensation interpolation, and it can improve the image quality after the interpolation.
The motion adaptive interpolation comprises a Bernard method represented in U.S. Pat. No. 5,027,201 and a Faroundja method represented in U.S. Pat. No. 5,159,451.
As described above, the conventional line repetition can be implemented as a simple hardware, however it lowers the image quality after the interpolation.
In addition, the conventional intra-field interpolation method can be implemented as a simple hardware also, however it has an error occurrence problem in the interpolation of the picture having the motion or image quality lowering problem due to the deterioration.
In addition, the conventional intra-field interpolation is better than the line repetition in the image quality and error occurrence aspect, however the picture is deteriorated when a still picture is interpolated.
The conventional motion adaptive interpolation can be implemented as a simple hardware on the comparison with the motion-compensation interpolation, and it can improve the image quality after the interpolation. However, a stepped noise occurs due to a simple vertical interpolation in an edge having a big motion.
In addition, the conventional motion adaptive interpolation uses a plurality of field memories and has a complicated processing process. Accordingly manufacture cost of an implementation circuit increases.
An object of the present invention is to provide a deinterlacing apparatus and a method thereof which are capable of improving the definition of a picture by performing interpolation appropriately in accordance with a motion degree and an edge direction of a field to be interpolated.
Another object of the present invention is to provide a deinterlacing apparatus and a method thereof which are capable of reducing the manufacture cost of a circuit to be implemented by simplifying the circuit.
Another object of the present invention is to provide a deinterlacing apparatus and method which overcome the limitations and disadvantages of the related art.
In order to achieve the above-described and other objects of the present invention, the deinerlacing apparatus in accordance with the present invention comprises a motion determining unit for mapping field data in a field region to be interpolated and perimeter field data around of it and detecting a BD (Brightness Difference) and a BPPD (Brightness Profile Pattern Difference) in order to yield a motion degree of a picture, a temporal interpolator for yielding a field average value about a field picture to be interpolated by averaging a pixel value of the former field and a pixel value of the after field, a spatial interpolator for detecting an edge direction comprised in the perimeter pixel values with inputs of the pixel value of the former field and after field about the field picture to :be interpolated, detecting a direction indicating a minimum region matching error in accordance with the detected edge direction, and yielding the intra-field interpolation value in accordance with the detected direction, and a soft switch unit for mixing the yielded intra-field interpolation value and the yielded field average value in accordance with the BD (Brightness Difference) and BPPD (Brightness Profile Pattern Difference), and outputting it to a vertical converter.
In order to achieve above-described and other objects, a deinterlacing method in accordance with the present invention for interpolating the present field d a t a by yielding a correlation between pixels in a certain region including a pixel to be interpolated in M number of field data and yielding an interpolation value of the pixel to be interpolated, comprises a sub-sampling process for performing a sub-sampling of perimeter pixels in a certain region centering around a pixel to be interpolated when the pixel to be interpolated does not exist on a horizontal or a vertical edge, a detecting process for detecting a varying direction of the pixel to be interpolated in the pixel region where the sub-sampling is performed, and a yielding process for yielding an interpolation value by referring to the detected direction.
In order to achieve above-described and other objects, a deinterlacing method in accordance with the present invention for detecting a motion degree by using a BD and BPPD of a picture in order to interpolate the picture by referring to the motion degree, comprises a pixel detecting process for detecting pixels in a certain region including a pixel to be interpolated in M number of field data corresponding to an interlaced scanning type picture, a varying direction detecting process for detecting a varying direction of the pixel to be interpolated by yielding a correlation between pixels in the certain region, a yielding process for yielding a region matching error of each region after dividing an observation window when the pixel to be interpolated does not exist on the horizontal or vertical edge in the certain region, and a yielding process for yielding an interpolation value to a direction indicating a minimum region matching error among the yielded errors of each region.
These and other objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. These and other objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.